An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters

AIM: To assess a novel method for automatic in-line detection of clinical mastitis.

METHODS: For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teatcups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alter- native ‘gold standards’ for diagnosing clinical mastitis.

RESULTS: In the pilot trial, 12–14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0.

CONCLUSION: The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.     

Effect of dry period length on the effect of an intramammary teat sealant on the risk of mastitis in cattle treated with antibiotics at drying off

AIM: The aim of this study was to evaluate, under farm conditions, the use of a teat sealant in addition to whole herd dry cow antibiotic therapy on the risk of clinical mastitis in dairy cattle at pasture, and to evaluate the impact of dry period length on that risk and the impact of the teat sealant on that risk.

METHODS: Dairy cows in three herds which used routine whole herd antibiotic therapy were randomly assigned to receive either treatment with an internal teat sealant (n=322) or no additional treatment (n=313) at drying-off between March and May 2010. All clinical mastitis cases during the dry period and to the end of the subsequent lactation were recorded by farm staff; factors affecting risk of clinical mastitis were then analysed using a Cox proportional hazards model.

RESULTS: Median duration of the dry period was 112 days with >25% of cows having a dry period >130 days. The incidence risk of mastitis during lactation for cows treated with teat sealant was 9.9 (95% CI=6.9–13.7) cases per 100 cows compared with 17.9 (95% CI=13.8–22.6) cases per 100 cows for cows treated with antibiotic alone. The addition of a teat sealant to dry cow antibiotic therapy decreased the risk of clinical mastitis only in the first 33 days after calving (Hazard risk 0.24 (95% CI=0.12–0.48)). Length of dry period did not significantly affect the risk of clinical mastitis, or the effect of adding teat sealant to dry cow antibiotic therapy on the risk of clinical mastitis.

CONCLUSIONS: In these herds where, based on the mastitis history, whole herd antibiotic therapy had been recommended, the use of a teat sealant significantly reduced the risk of clinical mastitis. This effect was limited to the first 33 days after calving; subsequently there was no significant effect of treatment. There was no effect of dry period length on risk of clinical mastitis, nor any significant interaction with treatment.

CLINICAL RELEVANCE: Combination therapy with teat sealant and antibiotic was effective under New Zealand conditions in herds using whole herd antibiotic treatment at drying off. Teat sealant reduced risk of clinical mastitis in cattle with dry periods substantially longer than 100 days, and there was no evidence that this effect changed as dry period length increased.     

A lymphoproliferative disease in Manx cats with similarities to autoimmune lymphoproliferative syndrome (ALPS) in people

In 2009–2010, an unusual lymphoproliferative disease was identified in multiple siblings from successive litters of Manx cats, suggesting a genetic predisposition to development of this disease. Presentation of disease in the cats had multiple similarities with the human disease ALPS, a rare inherited disorder that causes persistent lymphoproliferation, together with variable manifestations of autoimmunity and increased susceptibility to neoplasia. The majority of human ALPS patients have inherited Fas gene mutations, causing defective apoptosis of lymphocytes, although for a proportion of ALPS patients the underlying genetic mutations remain unknown. In order to identify the likely mode of inheritance of the disease, further matings of potential carrier cats are in progress. Studies to investigate the potential role of abnormalities in the Fas gene in the development of the disease in cats are also proposed. Identifying and further characterising the nature and mechanism of the disease in cats may allow better understanding of the development, progression, and treatment of ALPS in humans.     

Nephrogenic diabetes insipidus in a 14-year-old gelding

Abstract

CASE HISTORY: A 14-year-old Cleveland Bay cross gelding was presented with severe urinary incontinence that had been present for 1 year, and chronic polydipsia and polyuria over 4 years. Water intake had been recorded as 240 L over a 24-hour period.

CLINICAL FINDINGS: The horse had marked urinary incontinence and polyuria and polydipsia. The urine was markedly hyposthenuric, but no abnormalities on urinalysis were detected. There were no other abnormal clinical or neurological signs. Haematological and serum biochemical examinations showed no abnormalities and ultrasonographic and endoscopic examination of the urinary tract did not reveal any abnormalities. The horse underwent a modified water deprivation test and failed to concentrate its urine after 5 days. 1-desamino-8-d-arginine vasopressin (DDAVP) was administered I/V but the urine remained isosthenuric with a specific gravity of 1.010.

DIAGNOSIS: Nephrogenic diabetes insipidus. A definitive cause of the urinary incontinence was not found but overflow incontinence was considered a possibility.

CLINICAL RELEVENCE: Despite being a rare condition in the horse diabetes insipidus should be considered in cases of severe polydipsia and polyuria in mature horses.     

Alpaca plant poisonings: nitrate–nitrite and possible cyanide

Nitrate–nitrite poisoning killed four adult alpacas and induced the abortion of a full-term fetus after access to oaten hay ( Avena sativa ) containing 3.2% KNO₃ equivalent in dry matter. Necropsy findings were cyanosis, dark-coloured blood, and pulmonary congestion and oedema. Aqueous humour from two adults contained 25 mg NO₃/L and that from the fetus contained 10 mg NO₃/L. Cyanide poisoning possibly killed two adult wether alpacas that ate a garden-cultivated variety of Osteospermum ecklonis (South African daisy, bietou) with a cyanide potential of 6800 mg HCN/kg dry matter.     

Pre-hospital low-volume resuscitation with hemoglobin-glutamer-200 (Hb-200) in a canine hemorrhagic shock model

The Bowen Technique is a unique hands‐on therapy developed by Tom Bowen of Australia in the 1950s–60s and adapted for use in animals by Carol Bennett in 1997. It consists of a specific sequence of gentle, precise rolling moves done with thumb and fingers over muscle and tendon edges, across the direction of tension. A short waiting period follows each set of moves. Definitive mechanism(s) of action remains to be identified; however, autonomic nervous system modulation (heart rate variability studies) has been documented in humans. The technique has also been reported effective for back, hip, neck, and shoulder pain in human studies. Five geriatric dogs (13–16 years old) of various breeds were presented in a case series at a small animal clinic for primary complaints of stiffness, poor ambulation, and difficulty lying down/getting up. Four had hindlimb proprioceptive deficits; three had arthritic changes to coxofemoral joints and/or lumbar spine; three showed active indicators of pain (chronic pacing/panting; irritability; social withdrawal). All were on NSAID and/or nutritional therapy with unsatisfactory results. One dog had acupuncture weekly for over 1 year but no longer tolerated the needles. Treatment consisted of Animal Bowen at weekly or biweekly intervals. Three dogs were pain scored [0–10; average starting score 6.7 ± 0.6 (mean ± S.D.); range 6–7] by owner before and after treatment. All five dogs showed significant positive changes in attitude, and four had notable improvement in ease of ambulation, after the first treatment. Improvement was progressive over treatment course. Average post‐treatment score was 2.3 ± 2.1 (0, 3, 4); average pain score reduction was 4.3 ± 1.5 (range 3–6) after two to six treatments for the three dogs scored. One dog had complete resolution of hindlimb lameness of 5 years duration after three sessions. Animal Bowen, used alone or in conjunction with standard analgesics and other treatments, can be an effective therapy for chronic musculoskeletal conditions in dogs.     

Risk characterisation and management of sewage sludge on agricultural land-implications for the environment and the food-chain

The disposal of sewage wastes may cause severe environmental problems as was graphically demonstrated with pollution on Sydney's ocean beaches in recent years. Sewage sludges contain valuable plant nutrients and organic matter which can improve the fertility and structure of the soil. However, human parasites, pathogenic micro-organisms and chemicals capable of causing soil contamination, phytotoxicity and residues in animal products may also be present. Although sewage sludge is frequently spread on agricultural land overseas, it is not common in Australia and most states do not have specific regulations to minimise risk and promote good practice. A sludge-to-land program began in the Sydney region in 1990. It follows guidelines written by NSW Agriculture to encourage beneficial agricultural use of sludge by adoption of environmentally sustainable practices. This article describes the major risks to the food-chain and the environment, which may be associated with applying sewage sludge to agricultural land. It summarises how the risks are managed, and where further research data are required.